Prostheses for implantation in blood vessels or other similar organs of the living body are, in general, well known in the medical art. For example, prosthetic vascular grafts constructed of biocompatible materials, such as Dacron material or expanded, porous polytetrafluoroethylene (ePTFE) tubing, have been employed to replace or bypass damaged or occluded natural blood vessels. In general, endovascularly delivered grafts typically include a graft anchoring component that operates to hold the tubular graft in its intended position within the blood vessel. Most commonly, the graft anchoring component is one or more radially compressible stents that are radially expanded in vivo to anchor the tubular graft to the wall of a blood vessel or anatomical conduit. Thus, endovascular grafts are typically held in place by mechanical engagement and friction due to the apposition forces provided by the expandable stents.
In general, rather than performing an open surgical procedure to implant a graft that may be traumatic and invasive, endovascular grafts or stent-grafts are preferably deployed through a less invasive intraluminal delivery. These stent-grafts may include either self-expanding or balloon-expandable stent structures with a tubular graft component attached to the stent structure. The stent-graft can be reduced in diameter, by crimping onto a balloon catheter or by being contained within a sheath component of a delivery catheter, and advanced through the venous or arterial vasculature. More particularly, a lumen of the vasculature is accessed at a convenient and low trauma entry point, and the compressed or crimped stent-graft is routed through the vasculature to the site where the prosthesis is to be deployed. Once the stent-graft is positioned at a treatment site, the stent structure may be radially expanded or allowed to radially expand so that at least a portion of it contacts and substantially conforms to a portion of the surrounding interior wall of the lumen, e.g., the blood vessel wall or in another application an anatomical conduit, to hold the graft component firmly in place.
Grafting procedures are also known for treating aneurysms. Aneurysms result from weak, thinned blood vessel walls that “balloon” or expand due to aging, disease and/or blood pressure in the vessel. Consequently, aneurysmal vessels have a potential to rupture, causing internal bleeding and potentially life threatening conditions. Grafts are often used to isolate aneurysms or other blood vessel abnormalities from normal blood pressure, reducing pressure on the weakened vessel wall and reducing the chance of vessel rupture. As such, a tubular endovascular stent-graft may be placed within the blood vessel to span the aneurysm to create an artificial flow conduit through the aneurysm, thereby reducing if not nearly eliminating the exertion of blood pressure on the aneurysm.
Many current endovascular stent-grafts are complex and expensive to manufacture, often requiring numerous processing steps to separately form the stent structure and graft component and then additional processing steps to attach the graft component to the stent structure, which in some instances is rather labor intensive when the attachment is accomplished by suturing, i.e., sewing the graft component to the stent structure. Adding a graft component to the stent structure also increases the challenges of delivering the endovascular stent-graft via a catheter-based delivery system by increasing the crossing profile, or diameter, of the interventional device, and/or by decreasing the flexibility of the interventional device.
Thus, those of skill in the art seek improvements in providing an endovascular stent-graft having a sufficiently small crossing profile that is sufficiently flexible for readily tracking through the vasculature. In addition, a need remains in the art for a simplified manufacturing process for creating such a stent-graft. Embodiments of an endovascular implant described herein have an integral graft component that is manufactured in a single processing step.